Recorder.



C. W. BERRY.

RECORDER.

APPLICATION FILED SEPT-15, 1910.

1 ,2 1 6,272. Patented Feb. 20, 1917.

witnesses: 'wfiQf CHARLES W. BERRY, WEST SOMERVILLE, MASSACHUSETTS.

RECORDER.

Specification of Letters Patent.

Patented Feb. 20, 1917.

Application flied September 15, 1910. Serial No. 582,151.

To all whom it may concern:

Be it known that I, CHARLES W. BERRY, a citizen of the United States,and a resident of West Somerville, county of Middlesex, State ofMassachusetts, (whose post-ofiice address is 952 Broadway, WestSomerville, Massachusetts,) have invented an Improvement in Recorders,of which the following description, in connection with the accompanyingdrawings, is a specification, like letters on the drawings representinglike parts.

This invention relates to recorders, comprising improvements inmechanisms for recording the varying properties of a gaseous fluid.

The invention will be best understood by reference to the followingdescription when taken in connection with the accompanying illustrationof one specific embodiment thereof, while its scope will be moreparticularly pointed out in the appended claims.

In the drawings:

Figure 1 shows an explanatory diagram;

Fig. 2 shows in skeleton form an indicator embodying one form of myinvention for measuring temperature and volume variations of a fluid 3and Fig. 3 shows an indicator quite similar in construction but formeasuring temperaturepressure variations of a fluid.

Referring to the drawings and to the described embodiment of myinvention, I have there shown a recording indicator wherein by means ofelectrical and optical devices, displacements of a spot of light aremade to delineate the temperature fluctuations of a fluid, beingutilized in conjunction with a second set of displacements perpendicularto the first, which by mechanical devices are made proportional to thevariations in some other property of the fluid, such as the pressure orvolume.

Such an instrument may be usefully employed not only for securingdirectly a record of the temperature-pressure or temperature-volumevariations of the gas, but for drawing a closed diagram from which thework and heat diagrams may be constructed when it is impracticable touse a pressurevolume indicator either because the volume of theindicator piping and the indicator form too large a percentage of thecylinder volume, or because the pressure variations are very slight, orbecause of a non-cylindrical contour of the confining chamber, orbecause the variation in volume is not directly, or is only withdifficulty, measurable, or for any other reason. A temperature-volumeindicator would also find application upon the 1 third or fourth stagesof compound fluid compressors, while a temperature-pressure indicatorcould be used in any form of motor where none of the reciprocating partsis readily accessible, or where the construction of a suitable reducingmotion would be difiicult. Various other uses unnecessary to mentionvmay be had for such an instrument.

Any suitable means for recording temperature variations in a gaseousfluid may e utilized, as for example, by measuring the temperaturevariations directly through electro-optica-l devices such as a sensitivegalvanometer in circuit with two thermoelectric couples, one in circuitwith the gas to be measured, or an oscillograph in circuit with anexternal electromotive force and a resistance ribbon forming the chiefpart of the total resistance of the circuit and constructed of suchsubstance or alloy that its variation in electric resistance ispractically proportional to the temperature variations in thesurrounding fluid.

If such an instrument is placed, as represented in Fi 1, with its mirror1 at the center of a cyhndrical surface 2, the displacement of the rayof light would be proportional to the temperature fluctuations providedthe current fluctuations are proportional to the temperaturefluctuations. In case the current fluctuations deviate slightly from aratio of constant proportionality to the temperature, the calibration ofthe distorted record that would thus be produced by the measuringinstrument may be automatically eliminated and a correct result obtainedby distorting the surface from a true cylindrical form represented at 02into the form at 03, so that, for the same angular deflection of themirror, the perimetrical travel of the ray of light will be increased ordecreased, as the case may be, by the proper amount. The path traced bythe ray of light upon a photographic surface made to conform to thecontour of such distorted surface when spread out flat would then bedirectly proportional to the temperature fluctuations. By thus adjustingthe coutour of the cylindrical surface carrying the recording film to113 based upon the principle described, litefol-ring to Fig. 2, light isemitted from any suitable source t through the slot 5 in the casing 6 soas to fall in the form of a sheet upon the mirror 7 of a sensitivegalvanomctcr 8. From the galvanometer mirror it is i'clicctcd in a planeparallel with the axis of the mirror, so as to fall upon an opaquescreen 9 in which is formed the transverse and herein horizontal slot10.

The galvanometer is contained in an electric circuit 11, which latterincludes the battery or other source of electromotive force 12, togetherwith the plug 13, the latter being adapted to be inserted in theclearance space of an engine or compressor and carrying the very thinresistance ribbon it. By suitably'selecting the metal of which theribbon is composed and designing the circuit so that the ribboncomprises a large portion of the resistance of the circuit, the currentin the circuit will be made to vary substantially with the temperaturechanges in the ribbon, so that when the latter is introduced into theengine cylinder, or other fluid container, the ray of light will undergodeflections substantially proportional tothe temperature changes in thegas. Platinum or platinum iridium compound or other resistance metalscapable of withstanding a high degree of heat may be used for composingthe ribbon 14;.

The opaque screen 9 is given a vertical dis placement under theinfluence of a cross head connection 15 proportional to the pistondisplacement. The screen is carried by any suitable support, such as thevertical sliding rod 16, the spring 17 providing for the return of thescreen on the return stroke of the cross head.

Directly behind the screen is the sensitive plate, or preferably film,18 carried by the fixed holder or backing 19 fastened to the stationarybase 20. a

The backing will be curved like the walls of a cylinder, with the axisof the mirror as the center of curvature, if the mirror defiections areproportional to temperature changes, the film and screen being shaped toconform to the backing. If the deflections of the mirror are notproportional to temperature changes but depart more or less from strictproportionality, the shape of the backing and the film and screen willbe altered accordingly in accordance with the principles stated topresent a calibrating haircare shape and to provide for the automaticcalibration or correction of the instrument within itself.

In practice the entire device will be shielded by suitable'means toguard against the influence of external sources of light and against theeffect upon the sensitized recording surface of light other than thatreceived through the slot 10.

Tu Fig. 3 l have shown a modified form of indicator where directtemperature and pressure measurements are utilized. The construction andoperation of this indicator is substantially the same as that of thetemperature-volume indicator described, the screen 9, however, beinggiven a vertical reciprocation by means of a piston rod 21 connected toa piston (not shown) contained within an ordinary indicator cylinder 22,which latter has connections by appropriate piping with the enginecylinder so that the movements of the contained piston against anindicator spring are proportional to Va.- riations in the pressure ofthe fluid under measurement.

it will be evident that that portion of the light which is permitted topass through the slot in the opaque screen constitutes the recordingmedium and possesses two mutually perpendicular motions with relation tothe film which, in the case of the temperaturevolume indicator, drawsthe temperature record for each position of the piston through theengine cycle and, in the case of the temperature-pressure indicator,draws the temperature record for each value of the pressure throughoutthe cycle. I

Various other means may be used for securing the direct temperaturemeasurement than the optical device herein shown and while I have hereinshown the details of a specific form of instrument such disclosure isfor illustrative purposes, it being understood that the invention is notlimited to the particular details herein shown nor to any particularmanner of producing the temperature-caused or other displacements of therecording parts, but that extensive deviations may be made from theillustrated embodiment of the invention without departing from thespiritthereof.

- Claims:

1. A device for recording variations in the conditions of a fluidcomprising a recording element, means for holding a recording surfaceand means for roducing two mutually perpendicular disp acements betweenthe said element and surface, one following fluctuations in thetemperature and the other fol-lowing fluctuations in the volume of saidfluid.

2. In a temperature indicator the combination with a source of light ofmeans for h'old ing a sensitized surface, an oscillating reflector, anopaque screen for said surface containing a slot in a plane normal tothe axis of rotation of the reflector, electrical devices for impartingto the mirror a deflection such that the displacement of the reflectedray of light upon the sensitized surface is proportionate to thetemperature producing such deflection, and means for producing arelative displacement between the screen and the sensitized surfacenormal to the first displacement and proportional to the volume of thefluid substance undergoing said temperature fluctuations.

3. In an electrical temperature indicator the combination with anoptical recorder responsive to temperature fluctuations, said recorderhaving a movement deviating from a ratio of constant proportionality tothe temperature, of a recording surface having a suitable predeterminedshape to render the total displacement of the light ray on the saidsurface proportional to the change of temperature.

4. In an electrical temperature indicator the combination with anoptical recorder responsive to temperature fluctuations, of a recordingsurface, said recorder havino means for applying a recording ray to saisurface and the latter having a suitable predetermined shape to renderthe total displacement of the light ray on the said surface proportionalto the change of temperature, and means for producing a mutuallyperpendicular relative dis lacement between the point of application 0the recording ray and the surface proportional to variations in someother property of the fluid.

5. In an electrical temperature indicator the combination with anoptical recorder responsive to temperature fluctuations, of a recordingsurface, said recorder having means for applying a recording ray theretoand said surface having a suitable predetermined sha e to render thetotal displacement of the lig t ray on the said surface proportional tothe change of temperature, and

' light directly proportional to temperature changes producing suchdeflections.

7. In an optical temperature indicator, the combination withthermo-electrical responsive means for producing deflections of a ray oflight of a recording surface so shaped as to make the thereupon induceddeflections of the ray of light directly proportional to the temperaturechanges producing such deflections, and means for producing a secondrelative displacement between the recording surface and the point ofapplication of the ray of light perpendicular to the deflections of thelight ray.

8. In an indicator, the combination with a recording surface, of meansfor producing and oscillating a ray of light, means for making thethereupon induced deflections of the ray of light directly proportionalto the temperature chan es pro ucing such oscillations, and means orproducing a. seconddisplacement between the recording surface and theray of light perpendicular to the first displacement, and proportionalto variations in the volume of the fluid undergoing said temperaturefluctuations.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

CHARLES W. BERRY. Witnesses:

THOMAS B. Boo'ru, ROBERT H. KAMMLER.

